introduction to microorganisms

What is a microorganism?

Microorganisms are the subject of microbiology, which is the branch of science that

studies microorganisms. A microorganism can be one cell or a cluster of cells that can be

seen only by using a microscope. Microorganisms are organized into five fields of study:

bacteriology, virology, mycology, phycology, protozoology and parasitiology.

TYPES OF MICROORGANISMS

Pathogenic microorganism

An infection is caused by the infiltration of a disease causing microorganism known as

pathogenic microorganism. Some pathogenic microorganisms infect humans, other

animals and plant.

Example

Yersinia pestis is the microorganism that caused the Black Plague and killed more than

25 million Europeans. You might say that Yersinia pestis first infected fleas that were

carried into populated areas on the backs of rats. Rodents traveled on ships and then over

land in search of food. Fleas jumped from Rodents and bit people, transmitting Yersinia

pestis into the person’s blood stream.

Non-Pathogenic microorganism

Not all microorganisms are pathogens. In fact many microorganisms help to maintain

homeostasis in our bodies and are used in the production of food and other commercial

products. For example, flora are microorganisms found in our intestine that assist in the

digestion of food and play critical role in the formation of vitamins such as vitamin B and

vitamin K. They help by breaking down large molecules into smaller ones.